(1) Field of the Invention
The present invention relates to a gene sequence-reading instrument for reading the four bases of A, C, G, and U of the single stranded ribonucleic acid (RNA).
(2) Description of the Related Art
In the conventional DNA sequencers, a DNA was enzymatically cleaved at specific sequence region, a fluorophore was linked to the end of the cleaved region by a synthetic reaction, DNA was allowed to migrate at one direction by electrophoresis, and the length of the DNA was estimated by a laser beam from the time required for the migration. In this method, although the base at the end portion can be identified by an enzyme used for cleaving, bases in the remaining portion are completely unknown. Thus, the method required the sequencing of the end portion by cleaving the same DNA with various enzymes, and the reconstitution of the original DNA using a large scale computer.
DNA chips utilize the property that when RNA having a known sequence is spotted on a glass substrate, and the subject DNA is contaminated into the spotted region, the subject DNA can bind to the RNA of the known sequence only when the DNA has the consensus sequence with the RNA having the known sequence. Thus, sequences were estimated by spotting a variety of RNAs of known sequences and then detecting the presence or absence of the binding to the subject DNA. In either case, the coding sequence of the subject DNA cannot be directly read.
The conventional technology of DNA sequencers and DNA chips had the problems that they required the fragmentation of the original DNA, and even if the fragmented DNA sequences were partially identified, it was not easy to restore the original DNA. Thus, the total throughput required long hours, and besides the reliability of the restored DNA sequence was questioned.
In order to solve the above problems, it is an object of the present invention to detect each of four bases A, C, G, and U in the sequence and identify the gene sequence without the need of enzymatic cleavage.
In order to achieve the above purpose, the characteristics of the present invention is to detect an attractive force generated by hydrogen bonding with only one of the four bases A, C, G, and U in the sequence of single stranded RNA for each of the four bases.
Another characteristics of the present invention is to connect carbon nanotubes consisting of a very thin bundle with a diameter of a few nanometers to the end of the probe, and nucleotides composed of a base, a sugar and a phosphate is bound by chemical modification to one end of the connected carbon nanotube. In the subject RNA sequence, the property of bases that A binds only to U, G binds only to C due to complementarity is used to identify the base by the generation of an attractive force by the binding with only a specific base.
Furthermore, another characteristics of the present invention is to detect the attractive force generated by the complementarity of bases directly above during probe scanning, and to record it as a gene information such as positional information on a two-dimensional image.
Furthermore, another characteristics of the present invention is to display all base sequences in one RNA by superimposing specific points to each of separate four bases, e.g. the above positional information on one image.